The proposed research brings novel data to bear on the emergence of racial and socioeconomic disparities in health over the life course. We examine the intersection and mutual influence of three factors-socioeconomic status (SES), cognitive ability, and health itself. Extant research has demonstrated amply that indicators of SES predict health outcomes, that health affects socioeconomic attainment, and that cognitive ability predicts both educational attainment and health. But how do such associations between SES, cognitive ability, and health arise over the life course? And what role does racial discrimination play in influencing each of these factors to create disparities by race? A theory of dynamic interplay of these factors across the life course is posited to explain the emergence of racial and socioeconomic disparities in general health, obesity, respiratory function, and depression. A California-based cohort, the Child Health and Development Study-Adolescent Sample (CHDS-A) (n=2020), born 1959-1966, provides the novel data to evaluate this theory. Detailed information was collected at multiple time points from before birth until age 15-17 years for black and white offspring and their families. Sufficient numbers of black and white offspring from both high and low SES families were included in the sample. The data already collected include assessments during childhood and adolescence of SES, cognitive ability, and the selected domains of health. This project will add assessments at age 42-49 years. Analysis of the accumulated data will elucidate the relationships among fundamental sources of health disparities and inform the construction of policies and interventions designed to reduce such inequalities. PUBLIC HEALTH RELEVANCE: Health disparities by socioeconomic status and race represent major public health issues in need of resolution. This study will provide novel data from a bi-racial birth cohort that has been intensively followed through adolescence and is now in middle-age adulthood. The analysis of key data collected in the proposed study will create an unusual opportunity to understand when and why health disparities emerge over the life course, and further guidance for shaping the content and timing of interventions to ameliorate observed disparities.